define(['jquery', 'underscore', 'edx-ui-toolkit/js/utils/spec-helpers/ajax-helpers', 'URI', 'js/models/xblock_info',
        'js/views/paged_container', 'js/views/paging_header',
        'common/js/components/views/paging_footer', 'js/views/xblock'],
    function($, _, AjaxHelpers, URI, XBlockInfo, PagedContainer, PagingHeader, PagingFooter, XBlockView) {
        var htmlResponseTpl = _.template('' +
            '<div class="xblock-container-paging-parameters" ' +
                'data-start="<%= start %>" ' +
                'data-displayed="<%= displayed %>" ' +
                'data-total="<%= total %>" ' +
                'data-previews="<%= previews %>"></div>'
        );

        function getResponseHtml(override_options) {
            var default_options = {
                start: 0,
                displayed: PAGE_SIZE,
                total: PAGE_SIZE + 1,
                previews: true
            };
            var options = _.extend(default_options, override_options);
            return '<div class="xblock" data-request-token="request_token">' +
                '<div class="container-paging-header"></div>' +
                htmlResponseTpl(options) +
                '<div class="container-paging-footer"></div>' +
                '</div>';
        }

        var makePage = function(html_parameters) {
            return {
                resources: [],
                html: getResponseHtml(html_parameters)
            };
        };

        var PAGE_SIZE = 3;

        var mockFirstPage = makePage({
            start: 0,
            displayed: PAGE_SIZE,
            total: PAGE_SIZE + 1
        });

        var mockSecondPage = makePage({
            start: PAGE_SIZE,
            displayed: 1,
            total: PAGE_SIZE + 1
        });

        var mockEmptyPage = makePage({
            start: 0,
            displayed: 0,
            total: 0
        });

        var respondWithMockPage = function(requests, mockPage) {
            var request = AjaxHelpers.currentRequest(requests);
            if (typeof mockPage == 'undefined') {
                var url = new URI(request.url);
                var queryParameters = url.query(true); // Returns an object with each query parameter stored as a value
                var page = queryParameters.page_number;
                mockPage = page === '0' ? mockFirstPage : mockSecondPage;
            }
            AjaxHelpers.respondWithJson(requests, mockPage);
        };

        var MockPagingView = PagedContainer.extend({
            view: 'container_preview',
            el: $("<div><div class='xblock' data-request-token='test_request_token'/></div>"),
            model: new XBlockInfo({}, {parse: true})
        });

        describe('Paging Container', function() {
            var pagingContainer;

            beforeEach(function() {
                pagingContainer = new MockPagingView({
                    page_size: PAGE_SIZE,
                    page: jasmine.createSpyObj('page', ['updatePreviewButton', 'renderAddXBlockComponents'])
                });
            });

            describe('Container', function() {
                describe('rendering', function() {
                    it('should set show_previews', function() {
                        var requests = AjaxHelpers.requests(this);
                        expect(pagingContainer.collection.showChildrenPreviews).toBe(true); // precondition check

                        pagingContainer.setPage(0);
                        respondWithMockPage(requests, makePage({previews: false}));
                        expect(pagingContainer.collection.showChildrenPreviews).toBe(false);

                        pagingContainer.setPage(0);
                        respondWithMockPage(requests, makePage({previews: true}));
                        expect(pagingContainer.collection.showChildrenPreviews).toBe(true);
                    });
                });

                describe('setPage', function() {
                    it('can set the current page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('should not change page after a server error', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.setPage(1);
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });
                });

                describe('nextPage', function() {
                    it('does not move forward after a server error', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.nextPage();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('can move to the next page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.nextPage();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('can not move forward from the final page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.nextPage();
                        AjaxHelpers.expectNoRequests(requests);
                    });
                });

                describe('previousPage', function() {
                    it('can move back a page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.previousPage();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('can not move back from the first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.previousPage();
                        AjaxHelpers.expectNoRequests(requests);
                    });

                    it('does not move back after a server error', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.previousPage();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });
                });
            });

            describe('PagingHeader', function() {
                describe('Next page button', function() {
                    beforeEach(function() {
                        pagingContainer.render();
                    });

                    it('does not move forward if a server error occurs', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingHeader.$('.next-page-link').click();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('can move to the next page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingHeader.$('.next-page-link').click();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('should be enabled when there is at least one more page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.next-page-link')).not.toHaveClass('is-disabled');
                    });

                    it('should be disabled on the final page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.next-page-link')).toHaveClass('is-disabled');
                    });

                    it('should be disabled on an empty page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingHeader.$('.next-page-link')).toHaveClass('is-disabled');
                    });
                });

                describe('Previous page button', function() {
                    beforeEach(function() {
                        pagingContainer.render();
                    });

                    it('does not move back if a server error occurs', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.pagingHeader.$('.previous-page-link').click();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('can go back a page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.pagingHeader.$('.previous-page-link').click();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('should be disabled on the first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.previous-page-link')).toHaveClass('is-disabled');
                    });

                    it('should be enabled on the second page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.previous-page-link')).not.toHaveClass('is-disabled');
                    });

                    it('should be disabled for an empty page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingHeader.$('.previous-page-link')).toHaveClass('is-disabled');
                    });
                });

                describe('Page metadata section', function() {
                    it('shows the correct metadata for the current page', function() {
                        var requests = AjaxHelpers.requests(this),
                            message;
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        message = pagingContainer.pagingHeader.$('.meta').html().trim();
                        expect(message).toBe('<p>Showing <span class="count-current-shown">1-3</span>' +
                            ' out of <span class="count-total">4 total</span>, ' +
                            'sorted by <span class="sort-order">Date added</span> descending</p>');
                    });
                });

                describe('Children count label', function() {
                    it('should show correct count on first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.count-current-shown')).toHaveHtml('1-3');
                    });

                    it('should show correct count on second page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.count-current-shown')).toHaveHtml('4-4');
                    });

                    it('should show correct count for an empty collection', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingHeader.$('.count-current-shown')).toHaveHtml('0-0');
                    });
                });

                describe('Children total label', function() {
                    it('should show correct total on the first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.count-total')).toHaveText('4 total');
                    });

                    it('should show correct total on the second page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingHeader.$('.count-total')).toHaveText('4 total');
                    });

                    it('should show zero total for an empty collection', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingHeader.$('.count-total')).toHaveText('0 total');
                    });
                });
            });

            describe('PagingFooter', function() {
                describe('Next page button', function() {
                    beforeEach(function() {
                        // Render the page and header so that they can react to events
                        pagingContainer.render();
                    });

                    it('does not move forward if a server error occurs', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.next-page-link').click();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('can move to the next page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.next-page-link').click();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('should be enabled when there is at least one more page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.next-page-link')).not.toHaveClass('is-disabled');
                    });

                    it('should be disabled on the final page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.next-page-link')).toHaveClass('is-disabled');
                    });

                    it('should be disabled on an empty page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingFooter.$('.next-page-link')).toHaveClass('is-disabled');
                    });
                });

                describe('Previous page button', function() {
                    beforeEach(function() {
                        // Render the page and header so that they can react to events
                        pagingContainer.render();
                    });

                    it('does not move back if a server error occurs', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.previous-page-link').click();
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                    });

                    it('can go back a page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.previous-page-link').click();
                        respondWithMockPage(requests);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                    });

                    it('should be disabled on the first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.previous-page-link')).toHaveClass('is-disabled');
                    });

                    it('should be enabled on the second page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.previous-page-link')).not.toHaveClass('is-disabled');
                    });

                    it('should be disabled for an empty page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingFooter.$('.previous-page-link')).toHaveClass('is-disabled');
                    });
                });

                describe('Current page label', function() {
                    it('should show 1 on the first page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.current-page')).toHaveText('1');
                    });

                    it('should show 2 on the second page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(1);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.current-page')).toHaveText('2');
                    });

                    it('should show 1 for an empty collection', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingFooter.$('.current-page')).toHaveText('1');
                    });
                });

                describe('Page total label', function() {
                    it('should show the correct value with more than one page', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.total-pages')).toHaveText('2');
                    });

                    it('should show page 1 when there are no assets', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        AjaxHelpers.respondWithJson(requests, mockEmptyPage);
                        expect(pagingContainer.pagingFooter.$('.total-pages')).toHaveText('1');
                    });
                });

                describe('Page input field', function() {
                    var input;

                    it('should initially have a blank page input', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        expect(pagingContainer.pagingFooter.$('.page-number-input')).toHaveValue('');
                    });

                    it('should handle invalid page requests', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.page-number-input').val('abc');
                        pagingContainer.pagingFooter.$('.page-number-input').trigger('change');
                        expect(pagingContainer.collection.currentPage).toBe(0);
                        expect(pagingContainer.pagingFooter.$('.page-number-input')).toHaveValue('');
                    });

                    it('should switch pages via the input field', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.page-number-input').val('2');
                        pagingContainer.pagingFooter.$('.page-number-input').trigger('change');
                        AjaxHelpers.respondWithJson(requests, mockSecondPage);
                        expect(pagingContainer.collection.currentPage).toBe(1);
                        expect(pagingContainer.pagingFooter.$('.page-number-input')).toHaveValue('');
                    });

                    it('should handle AJAX failures when switching pages via the input field', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        pagingContainer.pagingFooter.$('.page-number-input').val('2');
                        pagingContainer.pagingFooter.$('.page-number-input').trigger('change');
                        requests[1].respond(500);
                        expect(pagingContainer.collection.currentPage).toBe(0);
                        expect(pagingContainer.pagingFooter.$('.page-number-input')).toHaveValue('');
                    });
                });
            });

            describe('Previews', function() {
                describe('Toggle Previews', function() {
                    var testSendsAjax,
                        defaultUrl = '/preview/xblock/handler/trigger_previews';

                    testSendsAjax = function(show_previews) {
                        it('should send ' + (!show_previews) + ' when showChildrenPreviews was ' + show_previews, function() {
                            var requests = AjaxHelpers.requests(this);
                            pagingContainer.collection.showChildrenPreviews = show_previews;
                            pagingContainer.togglePreviews();
                            AjaxHelpers.expectJsonRequest(requests, 'POST', defaultUrl, {showChildrenPreviews: !show_previews});
                            AjaxHelpers.respondWithJson(requests, {showChildrenPreviews: !show_previews});
                        });
                    };
                    testSendsAjax(true);
                    testSendsAjax(false);

                    it('should trigger render on success', function() {
                        spyOn(pagingContainer, 'render');
                        var requests = AjaxHelpers.requests(this);

                        pagingContainer.togglePreviews();
                        AjaxHelpers.respondWithJson(requests, {showChildrenPreviews: true});

                        expect(pagingContainer.render).toHaveBeenCalled();
                    });

                    it('should not trigger render on failure', function() {
                        spyOn(pagingContainer, 'render');
                        var requests = AjaxHelpers.requests(this);

                        pagingContainer.togglePreviews();
                        AjaxHelpers.respondWithError(requests);

                        expect(pagingContainer.render).not.toHaveBeenCalled();
                    });

                    it('should send force_render when new block causes page change', function() {
                        var requests = AjaxHelpers.requests(this);
                        pagingContainer.setPage(0);
                        respondWithMockPage(requests);
                        spyOn(pagingContainer, 'render');
                        var mockXBlockInfo = new XBlockInfo({id: 'mock-location'});
                        var mockXBlockView = new XBlockView({model: mockXBlockInfo});
                        mockXBlockView.model.id = 'mock-location';
                        pagingContainer.refresh(mockXBlockView, true);
                        expect(pagingContainer.render).toHaveBeenCalled();
                        expect(pagingContainer.render.calls.mostRecent().args[0].force_render).toEqual('mock-location');
                    });
                });
            });
        });
    });
